Display panel and display device

ABSTRACT

Provided are a display panel and a display device. The display panel includes a base substrate; a first transistor and a second transistor, where the first transistor and the second transistor are formed on the base substrate, the first transistor includes a first active layer, a first gate, a first source, and a first drain, the first active layer contains silicon, the second transistor includes a second active layer, a second gate, a second source, and a second drain, and the second active layer contains an oxide semiconductor and is disposed on one side of the first active layer facing away from the base substrate; and a first insulating layer and a second insulating layer, where the first insulating layer is disposed on one side of the second active layer facing away from the base substrate and between the second gate and the second active layer.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the priority to a Chinese patent application No.CN 202011615429.3 filed at the CNIPA on Dec. 30, 2020, disclosure ofwhich is incorporated herein by reference in its entirety.

TECHNICAL FIELD

Embodiments of the present disclosure relate to the field of displaytechnologies and, in particular, to a display panel and a displaydevice.

BACKGROUND

The organic light-emitting diode (OLED) display panel is widely popularwith people due to its advantages of self-illumination, high contrast,thin thickness, fast reaction speed and applicableness to a flexiblepanel.

The OLED element of the OLED display panel is a current-driven elementand thus needs to be provided with a corresponding pixel circuit and acorresponding driver circuit. The driver circuit provides a drive signalfor the pixel circuit so that the pixel circuit provides a drive currentfor the OLED element to drive the OLED element to emit light. The drivercircuit and the pixel circuit of the OLED display panel are eachprovided with a transistor. The transistor is often manufactured usingindium gallium zinc oxide (IGZO) to serve as an active layer so as toreduce the leakage current in the transistor. However, in the relatedart, the poor stability of the IGZO transistor further affects theperformance of the driver circuit and/or the pixel circuit, and thedisplay effect of the display panel is affected.

SUMMARY

Embodiments of the present disclosure provide a display panel and adisplay device to improve the stability of a second transistor andensure the good performance of the driver circuit.

In a first aspect, an embodiment of the present disclosure provides adisplay panel. The display panel includes a base substrate, a firsttransistor, a second transistor, a first insulating layer, and a secondinsulating layer.

The first transistor and the second transistor are formed on the basesubstrate, the first transistor includes a first active layer, a firstgate, a first source, and a first drain, and the first active layercontains silicon. The second transistor includes a second active layer,a second gate, a second source, and a second drain, and the secondactive layer contains an oxide semiconductor and is disposed on one sideof the first active layer facing away from the base substrate.

The first insulating layer is disposed on one side of the second activelayer facing away from the base substrate and between the second gateand the second active layer, and the second insulating layer is disposedon one side of the second active layer facing towards the basesubstrate.

A concentration of oxygen in the first insulating layer is lower than aconcentration of oxygen in the second insulating layer.

The display panel includes a pixel circuit and a driver circuitproviding a drive signal for the pixel circuit, where the driver circuitincludes the second transistor, and the pixel circuit includes the firsttransistor or the driver circuit includes the first transistor.

In a second aspect, an embodiment of the present disclosure furtherprovides a display device including the display panel described in thefirst aspect.

The display panel provided by the embodiment of the present disclosureincludes the first transistor and the second transistor. The firstactive layer of the first transistor contains silicon, and the secondactive layer of the second transistor contains an oxide semiconductor.The first insulating layer is located on the side of the second activelayer facing away from the base substrate, and the second insulatinglayer is located on the side of the second active layer facing towardsthe base substrate. The concentration of oxygen in the first insulatinglayer is lower than the concentration of oxygen in the second insulatinglayer, that is, the concentration of oxygen in the first insulatinglayer is appropriately reduced, so that the second active layer isprevented from being affected by the deficiency in the first insulatinglayer; meanwhile, the concentration of oxygen in the second insulatinglayer is appropriately increased, so that the normal function of thesecond active layer is ensured. Therefore, the stability of the secondtransistor is improved, and the good performance of the driver circuitis ensured.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram showing structures of a display panel according toan embodiment of the present disclosure;

FIG. 2 is a diagram showing structures of a display panel according toanother embodiment of the present disclosure;

FIG. 3 is a diagram showing structures of a display panel according toanother embodiment of the present disclosure;

FIG. 4 is a diagram showing structures of a display panel according toanother embodiment of the present disclosure;

FIG. 5 is a diagram showing structures of a display panel according toanother embodiment of the present disclosure;

FIG. 6 is a diagram showing structures of a display panel according toanother embodiment of the present disclosure;

FIG. 7 is a diagram showing structures of a display panel according toanother embodiment of the present disclosure;

FIG. 8 is a diagram showing structures of a display panel according toanother embodiment of the present disclosure; and

FIG. 9 is a diagram showing structures of a display device according toanother embodiment of the present disclosure.

DETAILED DESCRIPTION

Hereinafter the present disclosure will be further described in detailin conjunction with drawings and embodiments. It is to be understoodthat the embodiments set forth herein are intended to explain thepresent disclosure and not to limit the present disclosure.Additionally, it is to be noted that for ease of description, merelypart, not all, of the structures related to the present disclosure areillustrated in the drawings.

FIG. 1 is a diagram showing structures of a display panel according toan embodiment of the present disclosure. As shown in FIG. 1, a displaypanel 100 provided by the embodiment of the present disclosure includesa base substrate 10, a first transistor 20, a second transistor 30, afirst insulating layer 40, and a second insulating layer 41. The firsttransistor 20 and the second transistor 30 are formed on the basesubstrate 10. The first transistor 20 includes a first active layer 21,a first gate 22, a first source 23, and a first drain 24. The firstactive layer 21 contains silicon. The second transistor 30 includes asecond active layer 31, a second gate 32, a second source 33, and asecond drain 34. The second active layer 31 contains an oxidesemiconductor and is disposed on one side of the first active layer 21facing away from the base substrate 10. The first insulating layer 40 isdisposed on one side of the second active layer 31 facing away from thebase substrate 10 and between the second gate 32 and the second activelayer 31. The second insulating layer 41 is disposed on one side of thesecond active layer 31 facing towards the base substrate 10. Theconcentration of oxygen in the first insulating layer 40 is lower thanthe concentration of oxygen in the second insulating layer 41. Thedisplay panel 100 includes a pixel circuit (not shown in FIG. 1) and adriver circuit 50 providing a drive signal for the pixel circuit. Thedriver circuit 50 includes at least one second transistor 30. FIG. 1 isillustrated by using an example in which the driver circuit 50 includesboth the first transistor 20 and the second transistor 30.

The exemplary display panel 100 includes a display region AA and anon-display region NAA. The non-display region NAA is disposed on atleast one side of the display region AA. FIG. 1 is illustrated by usingan example in which the non-display region NAA is located on one side ofthe display region AA, where the driver circuit 50 is located in thenon-display region NAA. The driver circuit 50 provides a drive signalfor the pixel circuit (not shown in FIG. 1) in the display region AA tocause the pixel circuit to drive a light-emitting element which islocated in the same sub-pixel as the pixel circuit to emit light,thereby implementing the display of the display panel 100.

It is to be noted that in the present application, the first transistor20 and the second transistor 30 may be transistors in the drivercircuit, that is, the driver circuit 50 includes the first transistor 20or the second transistor 30. Additionally, the first transistor 20 andthe second transistor 30 may be transistors in the pixel circuit, thatis, the pixel circuit includes the first transistor 20 or the secondtransistor 30, for example, when the second transistor 30 is located inthe pixel circuit, the second transistor 30 may be a drive transistor ora switch transistor.

The concentration defined in the present application, if not speciallyrequired, is the atomic concentration, that is, the atomic content perunit area.

The exemplary driver circuit 50 includes the first transistor 20 and thesecond transistor 30, where the first transistor 20 may be a bottom-gatetransistor or a top-gate transistor. FIG. 1 is illustrated by using anexample in which the first transistor 20 is a top-gate transistor, thatis, the first gate 22 is disposed on one side of the first active layer21 facing away from the base substrate 10. Additionally, the secondinsulating layer 41 is disposed on one side of the first gate 22 facingaway from the base substrate 10. The second active layer 31 is disposedon one side of the second insulating layer 41 facing away from the basesubstrate 10. The first insulating layer 40 is disposed on one side ofthe second active layer facing away from the base substrate 10. Thesecond gate 32 is disposed on one side of the first insulating layer 40facing away from the base substrate 10. The first source 23, the firstdrain 24, the second source 33, and the second drain 34 are all disposedon one side of the second gate 32 facing away from the base substrate 10and are insulated from the second gate 32. The first source 23, thefirst drain 24, the second source 33, and the second drain 34 aredisposed in the same layer so that the process steps can be simplified.Additionally, the first active layer 21 in the first transistor 20contains silicon, optionally poly-silicon, that is, the first activelayer 21 is a poly-silicon active layer such as a low temperaturepoly-silicon (LTPS) active layer. The second active layer 31 in thesecond transistor 30 includes an oxide semiconductor, that is, thesecond active layer 31 is an oxide semiconductor active layer such as anIGZO active layer. The LTPS thin-film transistor has the advantages ofhigh carrier mobility, fast response, and low power consumption, and theoxide semiconductor thin-film transistor has the advantage of lowleakage current. When the driver circuit 50 includes the firsttransistor 20 and the second transistor 30, the driver circuit 50 hasthe advantages of high carrier mobility, fast response, low powerconsumption, and low leakage current, thereby ensuring the goodperformance of the driver circuit 50 and improving the displayperformance of the display panel 100.

Furthermore, the concentration of oxygen in the first insulating layer40 is lower than the concentration of oxygen in the second insulatinglayer 41. On one hand, the concentration of oxygen in the firstinsulating layer 40 is appropriately reduced, so that when the firstinsulating layer 40 is used as a gate insulating layer, a deficiencycaused by existence of a dangling bond in oxygen in the film formingprocess is avoided, and the problem that the existence of the deficiencyaffects the stability of the second transistor 30 is further avoided. Onthe other hand, the concentration of oxygen in the second insulatinglayer 41 is appropriately increased, so that the second active layer 31containing the oxide semiconductor is supplemented with oxygen, and thenormal function of the second active layer 31 is ensured. That is, inthis embodiment, the concentration of oxygen in the first insulatinglayer 40 is lower than the concentration of oxygen in the secondinsulating layer 41, so that the stability of the second transistor 30can be improved without affecting the normal function of the secondtransistor 30, thereby ensuring good performance of the driver circuit50.

It is to be noted that since the first insulating layer 40 is located onthe side of the second active layer 31 facing away from the basesubstrate 10 and between the second gate 32 and the second active layer31 and the second insulating layer 41 is located on the side of thesecond active layer 31 facing towards the base substrate 10, the firstinsulating layer 40 and the second insulating layer 41 may be in directcontact with the second active layer 31, which is shown in FIG. 1.Alternatively, the first insulating layer 40 and/or the secondinsulating layer 41 may not be in direct contact with the second activelayer 31. That is, other insulating layers are provided between thefirst insulating layer 40 and the second active layer 31 withoutaffecting the performance of the second transistor 30, and/or otherinsulating layers are provided between the second insulating layer 41and the second active layer 31, which is not specifically limited inthis embodiment.

In summary, the display panel provided by the embodiment of the presentdisclosure includes the first transistor and the second transistor. Thefirst active layer of the first transistor contains silicon, and thesecond active layer of the second transistor contains an oxidesemiconductor. The first insulating layer is located on the side of thesecond active layer facing away from the base substrate, and the secondinsulating layer is located on the side of the second active layerfacing towards the base substrate. The concentration of oxygen in thefirst insulating layer is lower than the concentration of oxygen in thesecond insulating layer, that is, the concentration of oxygen in thefirst insulating layer is appropriately reduced, so that the secondactive layer is prevented from being affected by the deficiency in thefirst insulating layer; meanwhile, the concentration of oxygen in thesecond insulating layer is appropriately increased, so that the normalfunction of the second active layer is ensured. Therefore, the stabilityof the second transistor is improved, and the good performance of thedriver circuit is ensured.

Optionally, A denotes a ratio of the concentration of oxygen to aconcentration of silicon in the first insulating layer 40, and B denotesa ratio of the concentration of oxygen to a concentration of silicon inthe second insulating layer 41, where A<B.

The first insulating layer 40 and the second insulating layer 41 eachinclude oxygen and silicon, for example, silicon oxide, but thematerials of the first insulating layer 40 and the second insulatinglayer 41 are not specifically limited in this embodiment, and thoseskilled in the art may select the materials according to actualsituations, so long as the first insulating layer 40 and the secondinsulating layer 41 each include oxygen and silicon.

Oxygen atoms and silicon atoms in the first insulating layer 40 and thesecond insulating layer 41 need to be bonded. In this embodiment, theratio of the concentration of oxygen to the concentration of silicon inthe first insulating layer 40 is appropriately reduced, so that thephenomenon of existence of dangling bonds in oxygen in the film formingprocess of the first insulating layer 40 can be reduced, and thestability of the second transistor 30 can be ensured. Moreover, thephenomenon of existence of dangling bonds in oxygen is prevented fromgetting more serious when the ratio of the concentration of oxygen tothe concentration of silicon is large, and thus deficiencies areprevented from getting more and capturing and affecting the carriers inthe second transistor 30. The problem of affecting the stability of thesecond transistor 30 is thus avoided.

Optionally, the first insulating layer 40 includes silicon oxideSiO_(x), and the second insulating layer 41 includes silicon oxideSiO_(y). Where x is a ratio of the number of oxygen atoms to the numberof silicon atoms in the first insulating layer 40, y is a ratio of thenumber of oxygen atoms to the number of silicon atoms in the secondinsulating layer 41, and x<y. That is, when the first insulating layer40 and the second insulating layer 41 each include silicon oxide, theratio of the concentration of oxygen to the concentration of silicon inthe first insulating layer 40 is appropriately reduced, so that thephenomenon of existence of dangling bonds in oxygen in the film formingprocess of the first insulating layer 40 can be reduced, and thestability of the second transistor 30 can be ensured. Moreover, thephenomenon of existence of dangling bonds in oxygen is prevented fromgetting more serious when the ratio of the concentration of oxygen tothe concentration of silicon is large, and thus deficiencies areprevented from getting more and capturing and affecting the carriers inthe second transistor 30. The problem of affecting the stability of thesecond transistor 30 is thus avoided.

FIG. 2 is a diagram showing structures of a display panel according toanother embodiment of the present disclosure. As shown in FIG. 2, apixel circuit 60 further includes a third transistor 70. The thirdtransistor 70 includes a third active layer 71, a third source 73, athird drain 74, and a fourth gate 72, and the third active layer 71contains an oxide semiconductor. The display panel 200 further includesa fourth insulating layer 43 and a fifth insulating layer 44. The fourthinsulating layer 43 is disposed on one side of the third active layer 71facing away from the base substrate 10 and between the third activelayer 71 and the fourth gate 72. The fifth insulating layer 44 isdisposed on one side of the third active layer 71 facing towards thebase substrate 10. The concentration of oxygen in the fourth insulatinglayer 43 is lower than the concentration of oxygen in the fifthinsulating layer 44. FIG. 4 is illustrated by using an example in whichthe pixel circuit 60 includes the first transistor 20.

As shown in FIG. 2, the display panel 200 includes a display region AAand a non-display region NAA, the driver circuit 50 is disposed in thenon-display region NAA, and the pixel circuit 60 is disposed in thedisplay region AA. The pixel circuit 60 includes the first transistor 20and the third transistor 70. The third active layer 71 in the thirdtransistor 70 includes an oxide semiconductor, that is, the third activelayer 71 is an oxide semiconductor active layer such as an IGZO activelayer. The leakage current of the oxide semiconductor thin-filmtransistor is very low, which can ensure that the leakage current in theworking process of the pixel circuit 60 is low. The first active layer21 in the first transistor 20 contains silicon, optionally poly-silicon,that is, the first active layer 21 is a poly-silicon active layer suchas a low temperature poly-silicon (LTPS) active layer. Furthermore, theLTPS thin-film transistor has the advantages of high carrier mobility,fast response, and low power consumption. Therefore, when the pixelcircuit 60 includes the first transistor 20 and the third transistor 70,the pixel circuit 60 has the advantages of high carrier mobility, fastresponse, low power consumption, and low leakage current, therebyensuring the good performance of the pixel circuit 60 and improving thedisplay performance of the display panel 200. In addition, in thisembodiment, the second transistor 30 in the driver circuit 50 is anoxide semiconductor transistor and the third transistor 70 in the pixelcircuit 60 is an oxide semiconductor transistor, so that goodperformance of the driver circuit 50 and the pixel circuit 60 isensured, and the display performance of the display panel 200 is furtherimproved.

Furthermore, in this embodiment, the concentration of oxygen in thefourth insulating layer 43 is lower than the concentration of oxygen inthe fifth insulating layer 44. On one hand, the concentration of oxygenin the fourth insulating layer 43 is appropriately reduced, so that whenthe fourth insulating layer 43 is used as a gate insulating layer, adeficiency caused by existence of a dangling bond in oxygen in the filmforming process is avoided, and the problem that the existence of thedeficiency affects the stability of the third transistor 70 is furtheravoided. On the other hand, the concentration of oxygen in the fifthinsulating layer 44 is appropriately increased, so that the third activelayer 71 containing the oxide semiconductor is supplemented with oxygen,and the normal function of the third active layer 71 is ensured. Thatis, in this embodiment, the concentration of oxygen in the fourthinsulating layer 43 is lower than the concentration of oxygen in thefifth insulating layer 44, so that the stability of the third transistor70 can be improved without affecting the normal function of the thirdtransistor 70, thereby ensuring good performance of the pixel circuit60.

It is to be noted that the fourth insulating layer 43 may be disposed inthe same layer as the first insulating layer 40, and the fifthinsulating layer 44 may be disposed in the same layer as the secondinsulating layer 41; or the fourth insulating layer 43 is not disposedin the same layer as the first insulating layer 40, and the fifthinsulating layer 44 is not disposed in the same layer as the secondinsulating layer 41. FIG. 4 is illustrated by using an example in whichthe fourth insulating layer 43 is disposed in the same layer as thefirst insulating layer 40 and the fifth insulating layer 44 is disposedin the same layer as the second insulating layer 41. Additionally, inthis embodiment, the third source 73 and the third drain 74 in the thirdtransistor 70 are disposed in the same layer as the second source 33 andthe second drain 34 in the second transistor 30 and the first source 23and the first drain 24 in the first transistor 20, thereby simplifyingthe process steps and improving the manufacturing efficiency of thedisplay panel.

On the basis of the preceding scheme, optionally, the third transistor70 is a switch transistor of the pixel circuit 60, R1 denotes adifference between a concentration C1 of oxygen in the first insulatinglayer 40 and a concentration C2 of oxygen in the second insulating layer41 and satisfies R1=C2−C1, and R2 denotes a difference between aconcentration C4 of oxygen in the fourth insulating layer 43 and aconcentration C5 of oxygen in the fifth insulating layer 44 is R2=C5−C4,where R1≥R2.

The pixel circuit 60 is sometimes applied to a low-frequency drivingmode. When the pixel circuit 60 is applied to the low-frequency drivingmode, a switch transistor in the pixel circuit 60 is in an off-state fora long time, while a transistor in the driver circuit 50 is turned onmore frequently. In the driver circuit 50, the difference between theconcentration of oxygen in the first insulating layer 40 and theconcentration of oxygen in the second insulating layer 41 isappropriately increased, that is, the concentration of oxygen in thefirst insulating layer 40 is lower, so that the influence ofdeficiencies on the second transistor 30 is reduced; the concentrationof oxygen in the second insulating layer 41 is higher, so that thesecond active layer 31 is supplemented with sufficient oxygen, and thedriver circuit 50 has high stability. Thus, even if the secondtransistor 30 in the driver circuit 50 turns on frequently, the overallcharacteristics of the driver circuit 50 can be ensured to be good.

Optionally, the third transistor 70 is a switch transistor of the pixelcircuit 60, and the concentration of oxygen in the first insulatinglayer 40 is lower than the concentration of oxygen in the fourthinsulating layer 43. That is, the concentration of oxygen in the firstinsulating layer 40 in the second transistor 30 of the driver circuit 50is much lower, so that when the first insulating layer 40 is used as thegate insulating layer, a deficiency caused by existence of a danglingbond in oxygen in the film forming process is avoided, and the problemthat the existence of the deficiency affects the stability of the secondtransistor 30 is further avoided. Thus, the second transistor 30 isensured to have high stability, and even if the second transistor 30 inthe driver circuit 50 turns on frequently, the overall characteristicsof the driver circuit 50 can also be ensured to be good.

It is to be noted that when the first insulating layer 40 and the fourthinsulating layer 43 are disposed in the same film layer, for example,different concentrations of oxygen may be implanted into the firstinsulating layer 40 and the fourth insulating layer 43 by the ionimplantation process so that the concentration of oxygen in the firstinsulating layer 40 is lower than the concentration of oxygen in thefourth insulating layer 43.

Optionally, the third transistor 70 is a drive transistor of the pixelcircuit 60, R1 denotes a difference between a concentration C1 of oxygenin the first insulating layer 40 and a concentration C2 of oxygen in thesecond insulating layer 41 and satisfies R1=C2−C1, and R2 denotes adifference between a concentration C4 of oxygen in the fourth insulatinglayer 43 and a concentration C5 of oxygen in the fifth insulating layer44 and satisfies R2=C5−C4, where R1≤R2.

The pixel circuit 60 is sometimes applied to a low-frequency drivingmode. When the pixel circuit 60 is applied to the low-frequency drivingmode, a drive transistor in the pixel circuit 60 is in an on statelonger than a transistor in the driver circuit 50. In the pixel circuit60, the difference between the concentration of oxygen in the fourthinsulating layer 43 and the concentration of oxygen in the fifthinsulating layer 44 is large, that is, the concentration of oxygen inthe fourth insulating layer 43 is much lower, so that the influence ofdeficiencies on the third transistor 70 is reduced; the concentration ofoxygen in the fifth insulating layer 44 is higher, so that the thirdactive layer 71 is supplemented with sufficient oxygen, and the thirdtransistor 70 is ensured to have high stability. Thus, even if the thirdtransistor 70 in the pixel circuit 60 is in the on state for a longtime, the overall characteristics of the pixel circuit 60 can also beensured to be good.

Optionally, the third transistor 70 is a drive transistor of the pixelcircuit 60; the concentration of oxygen in the first insulating layer 40is higher than the concentration of oxygen in the fourth insulatinglayer 43. That is, the concentration of oxygen in the fourth insulatinglayer 43 in the third transistor 70 of the pixel circuit 60 is lower, sothat when the fourth insulating layer 43 is used as the gate insulatinglayer, a deficiency caused by existence of a dangling bond in oxygen inthe film forming process is avoided, and the problem that the existenceof the deficiency affects the stability of the third transistor 70 isfurther avoided. Thus, the third transistor 70 is ensured to have highstability, and even if the third transistor 70 in the pixel circuit 60is in the on state for a longer time, the overall characteristics of thepixel circuit 60 can also be ensured to be good. In this case, when thefirst insulating layer 40 and the fourth insulating layer 43 aredisposed in the same film layer, different concentrations of oxygen mayalso be implanted into the first insulating layer 40 and the fourthinsulating layer 43 by the ion implantation process so that theconcentration of oxygen in the first insulating layer 40 is higher thanthe concentration of oxygen in the fourth insulating layer 43.

FIG. 3 is a diagram showing structures of a display panel according toanother embodiment of the present disclosure. As shown in FIG. 3, thedisplay panel 300 further includes a fourth transistor 80. The fourthtransistor 80 includes a fourth active layer 81, a fourth source 83, afourth drain 84, and a fifth gate 82. The fourth active layer 81contains an oxide semiconductor. The display panel 300 further includesa sixth insulating layer 45 and a seventh insulating layer 46. The sixthinsulating layer 45 is disposed on one side of the fourth active layer81 facing away from the base substrate 10 and between the fourth activelayer 81 and the fifth gate 82. The seventh insulating layer 46 isdisposed on one side of the fourth active layer 81 facing towards thebase substrate 10. The concentration of oxygen in the sixth insulatinglayer 45 is lower than the concentration of oxygen in the seventhinsulating layer 46.

It is to be noted that when the display panel 300 includes the fourthtransistor 80, the fourth transistor 80 may be a transistor in thedriver circuit 50 or a transistor in the pixel circuit 60, which is notspecifically limited in this embodiment. FIG. 3 is illustrated by usingan example in which the fourth transistor 80 is a transistor in thepixel circuit 60. Additionally, the specific structure of the pixelcircuit 60 is not limited in this embodiment. The pixel circuit 60 mayinclude, for example, seven transistors (7T) or nine transistors (9T).

Specifically, the pixel circuit 60 further includes the fourthtransistor 80. The fourth active layer 81 in the fourth transistor 80may also be an oxide semiconductor active layer such as an IGZO activelayer. That is, the two transistors in the pixel circuit 60 in thisembodiment are each an oxide semiconductor transistor, so that a leakagecurrent is ensured in the working process of the pixel circuit 60, andthe performance of the pixel circuit 60 is ensured to be good.Additionally, in this embodiment, the concentration of oxygen in thesixth insulating layer 45 is lower than the concentration of oxygen inthe seventh insulating layer 46. On one hand, the concentration ofoxygen in the sixth insulating layer 45 is appropriately reduced, sothat when the sixth insulating layer 45 is used as a gate insulatinglayer, a deficiency caused by existence of a dangling bond in oxygen inthe film forming process is avoided, and the problem that the existenceof the deficiency affects the stability of the fourth transistor 80 isfurther avoided. On the other hand, the concentration of oxygen in theseventh insulating layer 46 is appropriately increased, so that thefourth active layer 41 containing the oxide semiconductor issupplemented with oxygen, and the normal function of the fourth activelayer 41 is ensured. That is, in this embodiment, the concentration ofoxygen in the sixth insulating layer 45 is lower than the concentrationof oxygen in the seventh insulating layer 46, so that the stability ofthe fourth transistor 80 can be improved without affecting the normalfunction of the fourth transistor 80, thereby ensuring good performanceof the pixel circuit 60.

It is to be noted that the sixth insulating layer 45, the fourthinsulating layer 43, and the first insulating layer 40 may be disposedin the same film layer or different film layers, or any two of the abovelayers may be disposed in the same film layer. Similarly, the seventhinsulating layer 46, the fifth insulating layer 44, and the secondinsulating layer 41 may be disposed in the same film layer or differentfilm layers, or any two of the above layers may be disposed in the samefilm layer. FIG. 3 is illustrated by using an example in which the sixthinsulating layer 45, the fourth insulating layer 43, and the firstinsulating layer 40 are disposed in the same layer and the seventhinsulating layer 46, the fifth insulating layer 44, and the secondinsulating layer 41 are disposed in the same layer. Additionally, inthis embodiment, the fourth source 83 and the fourth drain 84 in thefourth transistor 80 are disposed in the same layer as the third source73 and the third drain 74 in the third transistor 70, the second source33 and the second drain 34 in the second transistor 30, and the firstsource 23 and the first drain 24 in the first transistor 30, therebysimplifying the process steps and improving the manufacturing efficiencyof the display panel.

On the basis of the preceding scheme, optionally, the third transistor70 is a drive transistor of the pixel circuit 60, and the fourthtransistor 80 is a switch transistor of the pixel circuit 60. Where R2denotes a difference between a concentration C4 of oxygen in the fourthinsulating layer 43 and a concentration C5 of oxygen in the fifthinsulating layer 44 and satisfies R2=C5−C4, and R3 denotes a differencebetween a concentration C6 of oxygen in the sixth insulating layer 45and a concentration C7 of oxygen in the seventh insulating layer 46 andsatisfies R3=C7−C6, where R2≥R3.

Generally speaking, in a pixel circuit, a transistor having a gateconnected to a scan signal or a light emission control signal is aswitch transistor, transistors except the switch transistor in the pixelcircuit are drive transistors which are connected in series on thetransmission path between a first power signal (e.g. PVDD signal) and asecond power signal (e.g. PVEE signal), and a data signal is writteninto the gate of the drive transistor. As the data signal is written,the potential of the gate of the drive transistor changes. The pixelcircuit is sometimes applied to a low-frequency driving mode. When thepixel circuit is applied to the low-frequency driving mode, a drivetransistor is in an on state longer than a switch transistor in thepixel circuit. In the pixel circuit 60 in this embodiment, thedifference between the concentration of oxygen in the fourth insulatinglayer 43 and the concentration of oxygen in the fifth insulating layer44 is large, that is, the concentration of oxygen in the fourthinsulating layer 43 is lower, so that the influence of deficiencies onthe third transistor 70 is reduced. The concentration of oxygen in thefifth insulating layer 44 is higher, so that the third active layer 71is supplemented with sufficient oxygen, and the third transistor 70 isensured to have high stability. Thus, even if the third transistor 70 inthe pixel circuit 60 is in the on state for a long time, the overallcharacteristics of the pixel circuit 60 can also be ensured to be good.

Optionally, the third transistor 70 is a drive transistor of the pixelcircuit 60, and the fourth transistor 80 is a switch transistor of thepixel circuit 60. The concentration of oxygen in the fourth insulatinglayer 43 is lower than the concentration of oxygen in the sixthinsulating layer 45. That is, the concentration of oxygen in the fourthinsulating layer 43 in the third transistor 70 of the pixel circuit 60is lower, so that when the fourth insulating layer 43 is used as thegate insulating layer, a deficiency caused by existence of a danglingbond in oxygen in the film forming process is avoided, and the problemthat the existence of the deficiency affects the stability of the thirdtransistor 70 is further avoided. Thus, the third transistor 70 isensured to have high stability, and even if the third transistor 70 inthe pixel circuit 60 is in the on state for a longer time, the overallcharacteristics of the pixel circuit 60 can also be ensured to be good.Similarly, when the fourth insulating layer 43 and the sixth insulatinglayer 45 are disposed in the same film layer, the concentration ofoxygen in the fourth insulating layer 43 may be made different from theconcentration of oxygen in the sixth insulating layer 45 by the ionimplantation process.

Optionally, with continued reference to FIG. 1, the display panel 100further includes a third insulating layer 42 disposed on one side of thesecond gate 32 facing away from the base substrate 10, where aconcentration of oxygen in the third insulating layer 42 is higher thanthe concentration of oxygen in the first insulating layer 40.

The third insulating layer 42 is an insulating layer on the side of thesecond gate 32 facing away from the base substrate 10. The concentrationof oxygen in the third insulating layer 42 is appropriately increased,so that the density of the third insulating layer 42 is increased.Therefore, the second transistor 30 is protected by the third insulatinglayer 42, and external water and oxygen, hydrogen and other elements areprevented from entering the second transistor 30 to affect theperformance of the second transistor 30.

Optionally, A denotes a ratio of the concentration of oxygen to aconcentration of silicon in the first insulating layer 40, and C denotesa ratio of the concentration of oxygen to a concentration of silicon inthe third insulating layer 42, where A<C. When the first insulatinglayer 40 and the second insulating layer 41 each include oxygen andsilicon, the ratio of the concentration of oxygen to the concentrationof silicon in the third insulating layer 42 is increased, so that thesecond transistor 30 is protected, avoiding a reduction in the densityof the third insulating layer 42 due to too low a concentration ofoxygen and too high a concentration of silicon in the third insulatinglayer 42, thereby avoiding influence on the ability of the thirdinsulating layer 42 to protect the second transistor 30.

Optionally, the concentration of oxygen in the third insulating layer 42is lower than the concentration of oxygen in the second insulating layer41. That is, the concentration of oxygen in the third insulating layer42 is higher than the concentration of oxygen in the first insulatinglayer 40 so as to protect the second transistor 30, but compared withthe concentration of oxygen in the second insulating layer 41, theconcentration of oxygen in the third insulating layer 42 is still lowerthan the concentration of oxygen in the second insulating layer 414.That is, the concentration of oxygen in the second insulating layer 41is higher, so that the second active layer 31 including the oxidesemiconductor is supplemented with oxygen, and the normal function ofthe second active layer 31 is ensured.

Optionally, B denotes a ratio of the concentration of oxygen to aconcentration of silicon in the second insulating layer 41, and Cdenotes a ratio of the concentration of oxygen to a concentration ofsilicon in the third insulating layer 42, where B>C. That is, when thesecond insulating layer 41 and the third insulating layer 42 eachinclude oxygen and silicon, the ratio of the concentration of oxygen tothe concentration of silicon in the second insulating layer 41 isincreased, so that the second active layer 31 including the oxidesemiconductor is supplemented with oxygen, and the normal function ofthe second active layer 31 is ensured.

Optionally, A denotes a ratio of the concentration of oxygen to aconcentration of silicon in the first insulating layer 40, B denotes aratio of the concentration of oxygen to a concentration of silicon inthe second insulating layer 41, and C denotes a ratio of theconcentration of oxygen to a concentration of silicon in the thirdinsulating layer 42, where (B−1)≤2(C−1)−(A−1). That is,(B−1)≤2(C−1)−(A−1), so that the concentration of oxygen to aconcentration of silicon in the first insulating layer 40 is lower, andthus the stability of the second transistor 30 can be improved. Adeficiency is avoided caused by existence of a dangling bond in oxygenin the film forming process when the first insulating layer 40 is usedas a gate insulating layer, and the problem that the existence of thedeficiency affects the stability of the second transistor 30 is furtheravoided.

On the basis of the preceding scheme, optionally,(B−1)−(C−1)≤½×[(C−1)−(A−1)].

In this embodiment, the ratio of the concentration of oxygen to theconcentration of silicon in the first insulating layer 40, the ratio Bof the concentration of oxygen to the concentration of silicon in thesecond insulating layer 41, and the ratio C of the concentration ofoxygen to the concentration of silicon in the third insulating layer 42satisfy that (B−1)−(C−1)≤½×[(C−1)−(A−1)]. Therefore, a deficiency causedby existence of a dangling bond in oxygen in the film forming process ofthe first insulating layer 40 is reduced, and the problem that theexistence of the deficiency affects the stability of the secondtransistor 30 is avoided. Meanwhile, the second active layer 31containing the oxide semiconductor is supplemented with oxygen throughthe second insulating layer 41, and the normal function of the secondactive layer 31 is ensured. Moreover, the density of the thirdinsulating layer 42 is increased through the sufficient oxygen toprotect the second transistor 30 and further improve the stability ofthe second transistor 30.

It is to be understood that the preceding example is merely illustratedwith the setting of concentrations of oxygen in the first insulatinglayer 40, the second insulating layer 41, and the third insulating layer43 close to the second transistor 30. However, when the display panel100 further includes the third transistor 70 and the fourth transistor80, for example, with continued reference to FIG. 3, the preceding ruleis also applicable to the fourth insulating layer 43, the fifthinsulating layer 44, and the insulating layer 47 on the side of thefourth insulating layer 43 facing away from the fifth insulating layer44, and the preceding rule is also applicable to the sixth insulatinglayer 45, the seventh insulating layer 46, and the insulating layer 48on the side of the sixth insulating layer 45 facing away from theseventh insulating layer 46. Repetition is not made herein.

The preceding embodiments are each illustrated by using an example inwhich the second transistor 30 is a top-gate transistor. Optionally, thesecond transistor 30 may also be a double-gate transistor. When thesecond transistor 30 is a double-gate transistor, in addition tosatisfying the rule of the concentration of oxygen in the insulatinglayer described in the preceding embodiments, the second transistor 30may also be individually set according to the characteristics of thedouble-gate transistor.

FIG. 4 is a diagram showing structures of a display panel 400 accordingto another embodiment of the present disclosure. As shown in FIG. 4, thesecond transistor 30 includes a third gate 35 disposed on one side ofthe second insulating layer 41 facing towards the base substrate 10,where a thickness H1 of the first insulating layer 40 is less than athickness H2 of the second insulating layer 41.

Specifically, the second transistor 30 includes not only the second gate32 but also the third gate 35, that is, the second transistor 30 is adouble-gate transistor, so that the mobility of carriers in the secondtransistor 30 can be enhanced, and the response ability of the secondtransistor 30 can be enhanced. It is to be noted that the secondtransistor 30 may be an oxide semiconductor transistor and generallyspeaking, the volume of the oxide semiconductor transistor is large, soit is beneficial to reducing the volume of the second transistor 30 byproviding the second transistor 30 as a double-gate transistor with atop gate and a bottom gate stacked. The area of the non-display regionNAA where the driver circuit 50 is located is thus reduced, achievingthe narrow bezel of the display panel 100. Additionally, the thicknessH1 of the first insulating layer 40 is less than the thickness H2 of thesecond insulating layer 41, that is, the thickness of the insulatinglayer of a main gate is less than the thickness of the insulating layerof an assist gate, so that the ability of the main gate to control thesecond transistor 30 is ensured.

When the second transistor 30 includes the third gate 35 located on theside of the second insulating layer 41 facing towards the base substrate10, optionally, in the second insulating layer 41, the concentration ofoxygen on the side facing towards the second active layer 31 is higherthan the concentration of oxygen on the side facing away from the secondactive layer 31.

Such setting has the following advantages: on one hand, in the secondinsulating layer 41, the concentration of oxygen on the side facingtowards the second active layer 31 is higher so that the second activelayer 31 containing the oxide semiconductor is supplemented withsufficient oxygen and the normal function of the second active layer 31is ensured; on the other hand, in the second insulating layer 41, theconcentration of oxygen on the side facing away from the second activelayer 31 is lower so that a deficiency caused by existence of a danglingbond in oxygen in the film forming process of the second insulatinglayer 41 is avoided, and the problem that the existence of thedeficiency affects the stability of the second transistor 30 is furtheravoided. Thus, the second transistor 30 is ensured to have goodperformance.

On the basis of the preceding scheme, FIG. 5 is a diagram showingstructures of a display panel 500 according to another embodiment of thepresent disclosure. As shown in FIG. 5, the second insulating layer 41includes a first sub-insulating layer 411 and a second sub-insulatinglayer 412, the second sub-insulating layer 412 is disposed on one sideof the first sub-insulating layer 411 facing away from the second activelayer 31, and the first sub-insulating layer 411 and the secondsub-insulating layer 412 each contains silicon oxide, where aconcentration of oxygen in the first sub-insulating layer 411 is higherthan a concentration of oxygen in the second sub-insulating layer 412.

In this embodiment, the first sub-insulating layer 411 and the secondsub-insulating layer 412 each includes silicon oxide, but concentrationsof oxygen in the first sub-insulating layer 411 and the secondsub-insulating layer 412 are different, for example, the concentrationof oxygen in the first sub-insulating layer 411 is higher than theconcentration of oxygen in the second sub-insulating layer 412. That is,the concentration of oxygen in the first sub-insulating layer 411 isappropriately increased, so that the second active layer 31 includingthe oxide semiconductor is supplemented with sufficient oxygen and thenormal function of the second active layer 31 is ensured. Meanwhile, theconcentration of oxygen in the second sub-insulating layer 412 isappropriately reduced so that a deficiency caused by existence of adangling bond in oxygen in the film forming process of the secondsub-insulating layer 412 is avoided, and the problem that the existenceof the deficiency affects the stability of the second transistor 30 isfurther avoided. Thus, the second transistor 30 is ensured to have goodperformance.

On the basis of the preceding scheme, optionally, a concentration ofhydrogen in the second sub-insulating layer 412 is higher than aconcentration of hydrogen in the first sub-insulating layer 411. Thedeficiency caused by existence of a dangling bond in oxygen inside thesecond sub-insulating layer 412 is repaired by hydrogen in the secondsub-insulating layer 412, so that the stability of the second transistor30 is ensured, and the performance of the second transistor 30 isfurther improved.

It is to be noted that FIG. 5 is illustrated by merely using an examplein which the second transistor 30 is a double-gate transistor. In thismanner, in FIG. 5, the relationship between the thickness H1 of thefirst insulating layer 40 and the thickness H2 of the second insulatinglayer 41 is described, the variation in the concentration of oxygen inthe second insulating layer 41 is described, and when the secondinsulating layer 41 includes the first sub-insulating layer 411 and thesecond sub-insulating layer 412, the materials of and the concentrationrelationship of oxygen in the first sub-insulating layer 411 and thesecond sub-insulating layer 412 are defined, and the concentrationrelationship of hydrogen in the first sub-insulating layer 411 and thesecond sub-insulating layer 412 is defined. It is to be understood thatwhen the third transistor 70 is a double-gate transistor, the fourthinsulating layer 43 and the fifth insulating layer 44 also satisfy thepreceding relationship. When the fourth transistor 80 is a double-gatetransistor, the sixth insulating layer 45 and the seventh insulatinglayer 46 also satisfy the preceding relationship. Repetition is not madeherein.

On the basis of the preceding schemes, FIG. 6 is a diagram showingstructures of a display panel 600 according to another embodiment of thepresent disclosure. As shown in FIG. 6, the base substrate 10 in theembodiment of the present disclosure may be a flexible base substrate ora rigid base substrate, which is not limited in the embodiment of thepresent disclosure. When the base substrate 10 is a flexible substrate,the base substrate 10 may include a polyimide substrate to ensure thatthe flexible substrate has good high temperature resistance and goodinsulation performance. The base substrate 10 may include one layer ofpolyimide substrate or two layers of polyimide substrates, which is notlimited in the embodiment of the present disclosure. When the basesubstrate 10 includes one layer of polyimide substrate, the film layerof the base substrate 10 has a simple structure and can be manufacturedwith a simple process, facilitating the implementation of designrequirements of the base substrate 10 and the entire display panel beinglight and thin. When the base substrate 10 includes at least two layersof polyimide substrates, a buffer layer is further provided between thepolyimide substrates to enhance adhesion between the polyimidesubstrates; when the base substrate 10 is formed by polyimide substratesbeing stacked with the buffer layer, some external impurities and/orwater vapor can be prevented from entering into the substrate on thebottom to affect the first active layer 21. Furthermore, since thepolyimide substrate is generally manufactured on a rigid substrate, therigid substrate is generally lift off by the laser lift-off techniqueafter the driver circuit 50, the pixel circuit, and the light-emittingelement are manufactured on the base substrate 10. The polyimidesubstrate may be damaged when the rigid substrate is lift off by laser.Therefore, when the base substrate 10 includes at least two polyimidesubstrates, for example, including a first polyimide substrate and asecond polyimide substrate, a first buffer layer is provided between thefirst polyimide substrate and the second polyimide substrate, and asecond buffer layer is provided between the second polyimide substrateand the first active layer 21. The first polyimide substrate ismanufactured on the rigid substrate, and the driver circuit 50 and thepixel circuit are manufactured on the second buffer layer. Therefore,even if the first polyimide substrate may be damaged when the rigidsubstrate is lift off by laser, the integrity of the second polyimidesubstrate and the integrity of the second buffer layer on the secondpolyimide substrate can be ensured, thereby ensuring the integrity ofthe entire display panel. FIG. 6 is illustrated by merely using anexample in which the base substrate 10 is a flexible substrate andincludes a first flexible substrate 11 and a second flexible substrate13, which are polyimides, respectively, as well as a first buffer layer12 between the first flexible substrate 11 and the second flexiblesubstrate 13 and a second buffer layer 14 between the second flexiblesubstrate 13 and the first active layer 21.

Based on the same concept, an embodiment of the present disclosurefurther provides a display panel. FIG. 7 is a diagram showing structuresof a display panel 700 according to another embodiment of the presentdisclosure. As shown in FIG. 7, display panel 700 provided by theembodiment of the present disclosure includes a base substrate 10, afirst transistor 20, a second transistor 30, a first insulating layer40, and a second insulating layer 41. The first transistor 20 and thesecond transistor 30 are formed on the base substrate 10. The firsttransistor 20 includes a first active layer 21, a first gate 22, a firstsource 23, and a first drain 24. The first active layer 21 containssilicon. The second transistor 30 includes a second active layer 31, asecond gate 32, a third gate 35, a second source 33, and a second drain34. The second active layer 31 contains an oxide semiconductor and isdisposed on one side of the first active layer 21 facing away from thebase substrate 10. The first insulating layer 40 and the secondinsulating layer 42 are located on two sides of the second active layer31, respectively. The first insulating layer 40 is disposed between thesecond gate 32 and the second active layer 31. The second insulatinglayer 41 is disposed between the third gate 35 and the second activelayer 31. The thickness H1 of the first insulating layer 40 is less thanthe thickness H2 of the second insulating layer 41. The concentration ofoxygen in the first insulating layer 40 is lower than the concentrationof oxygen in the second insulating layer 41. The display panel 700includes a pixel circuit (not shown in FIG. 7) and a driver circuit 50providing a drive signal for the pixel circuit. The driver circuit 50includes at least one second transistor 30. FIG. 7 is illustrated byusing an example in which the driver circuit 50 includes the firsttransistor 20 and the second transistor 30.

Referring to FIG. 7, when the second gate 32 is the main gate of thesecond transistor 30 and is the top gate of the second transistor 30,the thickness H1 of the first insulating layer 40 corresponding to themain gate is set to be less than the thickness H2 of the secondinsulating layer 41 corresponding to the assist gate, thereby ensuringthe ability of the main gate to control the second transistor 30.

FIG. 8 is a diagram showing structure of a display panel 800 accordingto another embodiment of the present disclosure. As shown in FIG. 8,when the second gate 32 is the main gate of the second transistor 30 andis the bottom gate of the second transistor 30, the thickness H1 of thefirst insulating layer 40 corresponding to the main gate is set to beless than the thickness H2 of the second insulating layer 41corresponding to the assist gate to ensure the ability of the main gateto control the second transistor 30.

In the display panel provided by the embodiment of the presentdisclosure, the concentration of oxygen in the first insulating layer(that is, the insulating layer of the main gate) is lower than theconcentration of oxygen in the second insulating layer (that is, theinsulating layer of the assist gate), that is, the concentration ofoxygen in the first insulating layer is appropriately reduced to avoidthe influence of the deficiency in the first insulating layer on thesecond active layer. The concentration of oxygen in the secondinsulating layer is appropriately increased to ensure the normalfunction of the second active layer, thereby improving the stability ofthe second transistor and ensuring the good performance of the drivercircuit. Meanwhile, the thickness of the first insulating layer (thatis, the insulating layer of the main gate) is set to be less than thethickness of the second insulating layer (that is, the insulating layerof the assist gate) to ensure the ability of the main gate to controlthe second transistor.

Based on the same concept, an embodiment of the present disclosurefurther provides a display device. The display device includes anydisplay panel provided in the preceding embodiments. Exemplarily, asshown in FIG. 9, a display device 1000 includes the display panel 100.Therefore, the display device also has the beneficial effects of thedisplay panel described in the preceding embodiments, and for the samedetails, reference may be made to the description of the precedingdisplay panel, and repetition will not made herein.

A display device 1000 provided in accordance with the embodiments of thepresent disclosure may be the phone shown in FIG. 9, or may be anyelectronic product with a display function, including but not limitedto: televisions, laptops, desktop displays, tablet computers, digitalcameras, smart bracelets, smart glasses, in-vehicle displays,industry-controlling equipment, medical displays, touch interactiveterminals, etc., which will not be specifically limited in theembodiment of the present disclosure.

It is to be noted that the preceding are merely preferred embodiments ofthe present disclosure and the technical principles used therein. It isto be understood by those skilled in the art that the present disclosureis not limited to the embodiments described herein. Those skilled in theart can make various apparent modifications, adaptations, andsubstitutions without departing from the scope of the presentdisclosure. Therefore, while the present disclosure has been describedin detail via the preceding embodiments, the present disclosure is notlimited to the preceding embodiments and may include equivalentembodiments without departing from the concept of the presentdisclosure. The scope of the present disclosure is determined by thescope of the appended claims.

What is claimed is:
 1. A display panel, comprising: a base substrate; afirst transistor and a second transistor, wherein the first transistorand the second transistor are formed on the base substrate, wherein thefirst transistor comprises a first active layer, a first gate, a firstsource and a first drain, and wherein the first active layer comprisessilicon; wherein the second transistor comprises a second active layer,a second gate, a second source, and a second drain, and wherein thesecond active layer comprises an oxide semiconductor and is disposed onone side of the first active layer facing away from the base substrate;and a first insulating layer and a second insulating layer, wherein thefirst insulating layer is disposed on one side of the second activelayer facing away from the base substrate and between the second gateand the second active layer, and wherein the second insulating layer isdisposed on one side of the second active layer facing towards the basesubstrate; wherein a concentration of oxygen in the first insulatinglayer is lower than a concentration of oxygen in the second insulatinglayer; wherein the display panel comprises a pixel circuit and a drivercircuit providing a drive signal for the pixel circuit, wherein thedriver circuit comprises the second transistor, and wherein the pixelcircuit comprises the first transistor or wherein the driver circuitcomprises the first transistor.
 2. The display panel of claim 1, whereina ratio of the concentration of oxygen to a concentration of silicon inthe first insulating layer is A, wherein a ratio of the concentration ofoxygen to a concentration of silicon in the second insulating layer isB, andA<B.
 3. The display panel of claim 1, wherein the first insulating layercomprises silicon oxide SiO_(x) and the second insulating layercomprises silicon oxide SiO_(y), wherein x is a ratio of a number ofoxygen atoms to a number of silicon atoms in the first insulating layer,wherein y is a ratio of a number of oxygen atoms to a number of siliconatoms in the second insulating layer, and wherein x<y.
 4. The displaypanel of claim 1, wherein the second transistor comprises a third gatedisposed on one side of the second insulating layer facing towards thebase substrate, and wherein a thickness of the first insulating layer isless than a thickness of the second insulating layer.
 5. The displaypanel of claim 4, wherein in the second insulating layer, aconcentration of oxygen on one side facing towards the second activelayer is higher than a concentration of oxygen on one side facing awayfrom the second active layer.
 6. The display panel of claim 5, whereinthe second insulating layer comprises a first sub-insulating layer and asecond sub-insulating layer, wherein the second sub-insulating layer isdisposed on one side of the first sub-insulating layer facing away fromthe second active layer, wherein each of the first sub-insulating layerand the second sub-insulating layer comprises silicon oxide, and whereina concentration of oxygen in the first sub-insulating layer is higherthan a concentration of oxygen in the second sub-insulating layer. 7.The display panel of claim 6, wherein a concentration of hydrogen in thesecond sub-insulating layer is higher than a concentration of oxygen inthe first sub-insulating layer.
 8. The display panel of claim 1, whereinthe display panel further comprises a third insulating layer disposed onone side of the second gate facing away from the base substrate, andwherein a concentration of oxygen in the third insulating layer ishigher than the concentration of oxygen in the first insulating layer.9. The display panel of claim 8, wherein the concentration of oxygen inthe third insulating layer is lower than the concentration of oxygen inthe second insulating layer.
 10. The display panel of claim 8, wherein aratio of the concentration of oxygen to a concentration of silicon inthe first insulating layer is A, wherein a ratio of the concentration ofoxygen to a concentration of silicon in the second insulating layer isB, and wherein a ratio of the concentration of oxygen to a concentrationof silicon in the third insulating layer is C, wherein(B−1)≤2(C−1)−(A−1).
 11. The display panel of claim 12, wherein(B−1)−(C−1)≤½×[(C−1)−(A−1)].
 12. The display panel of claim 1, whereinthe pixel circuit further comprises a third transistor, wherein thethird transistor comprises a third active layer, a third source, a thirddrain, and a fourth gate, and the third active layer contains an oxidesemiconductor; and wherein the display panel further comprises a fourthinsulating layer and a fifth insulating layer, wherein the fourthinsulating layer is disposed on one side of the third active layerfacing away from the base substrate and between the third active layerand the fourth gate, and wherein the fifth insulating layer is disposedon one side of the third active layer facing towards the base substrate,wherein a concentration of oxygen in the fourth insulating layer islower than a concentration of oxygen in the fifth insulating layer. 13.The display panel of claim 12, wherein the third transistor is a switchtransistor of the pixel circuit; and wherein a difference between theconcentration C1 of oxygen in the first insulating layer and theconcentration C2 of oxygen in the second insulating layer is R1=C2−C1,wherein a difference between the concentration C4 of oxygen in thefourth insulating layer and the concentration C5 of oxygen in the fifthinsulating layer is R2=C5−C4, andR1≥R2.
 14. The display panel of claim 12, wherein the third transistoris a switch transistor of the pixel circuit, and wherein theconcentration of oxygen in the first insulating layer is lower than theconcentration of oxygen in the fourth insulating layer.
 15. The displaypanel of claim 12, wherein the third transistor is a drive transistor ofthe pixel circuit; and wherein a difference between the concentration C1of oxygen in the first insulating layer and the concentration C2 ofoxygen in the second insulating layer is R1=C2−C1, and wherein adifference between the concentration C4 of oxygen in the fourthinsulating layer and the concentration C5 of oxygen in the fifthinsulating layer is R2=C5−C4, and wherein R1≤R2.
 16. The display panelof claim 12, wherein the third transistor is a drive transistor of thepixel circuit; and wherein the concentration of oxygen in the firstinsulating layer is higher than the concentration of oxygen in thefourth insulating layer.
 17. The display panel of claim 12, wherein thedisplay panel further comprises a fourth transistor, wherein the fourthtransistor comprises a fourth active layer, a fourth source, a fourthdrain, and a fifth gate, and wherein the fourth active layer contains anoxide semiconductor; and wherein the display panel further comprises asixth insulating layer and a seventh insulating layer, wherein the sixthinsulating layer is disposed on one side of the fourth active layerfacing away from the base substrate and between the fourth active layerand the fifth gate, and wherein the seventh insulating layer is disposedon one side of the fourth active layer facing towards the basesubstrate, wherein a concentration of oxygen in the sixth insulatinglayer is lower than a concentration of oxygen in the seventh insulatinglayer.
 18. The display panel of claim 17, wherein the third transistoris a drive transistor of the pixel circuit, and wherein the fourthtransistor is a switch transistor of the pixel circuit, wherein adifference between the concentration C4 of oxygen in the fourthinsulating layer and the concentration C5 of oxygen in the fifthinsulating layer is R2=C5−C4, wherein a difference between theconcentration C6 of oxygen in the sixth insulating layer and theconcentration C7 of oxygen in the seventh insulating layer is R3=C7−C6,and whereinR2≥R3.
 19. The display panel of claim 17, wherein the third transistoris a drive transistor of the pixel circuit, and wherein the fourthtransistor is a switch transistor of the pixel circuit, and the whereinconcentration of oxygen in the fourth insulating layer is lower than theconcentration of oxygen in the sixth insulating layer.
 20. A displaypanel, comprising: a base substrate; a first transistor and a secondtransistor, wherein the first transistor and the second transistor areformed on the base substrate, wherein the first transistor comprises afirst active layer, a first gate, a first source, and a first drain,wherein the first active layer comprises silicon, wherein the secondtransistor comprises a second active layer, a second gate, a third gate,a second source, and a second drain, and wherein the second active layercomprises an oxide semiconductor and is disposed on one side of thefirst active layer facing away from the base substrate; and a firstinsulating layer and a second insulating layer, wherein the firstinsulating layer and the second insulating layer are disposed on twosides of the second active layer, respectively, wherein the firstinsulating layer is disposed between the second gate and the secondactive layer, wherein the second insulating layer is disposed betweenthe third gate and the second active layer, and wherein a thickness ofthe first insulating layer is less than a thickness of the secondinsulating layer, wherein a concentration of oxygen in the firstinsulating layer is lower than a concentration of oxygen in the secondinsulating layer; wherein the display panel comprises a pixel circuitand a driver circuit providing a drive signal for the pixel circuit,wherein the driver circuit comprises the second transistor, and whereinthe pixel circuit comprises the first transistor or wherein the drivercircuit comprises the first transistor.